The present invention relates to an engine cutter, and in particular to an engine cutter comprising a disk cutter to be driven by an air-cooled internal combustion engine such as a small air-cooled two stroke gasoline engine, and a fan for sucking and discharging dust to be generated for instance from the cutting work of concrete-molded materials by the disk cutter.
As for the conventional engine cutter which is actually employed now, there is known that comprises a disk cutter, an air-cooled internal combustion engine for rotating the disk cutter, a safety cover partially encasing the disk cutter, a dust-trapping portion which is mounted on the safety cover for trapping and discharging dust to be generated from the cutting work by the disk cutter, and a fan to be driven by the engine and attached to the safety cover for generating an air flow for sucking and discharging the dust that has been trapped in the dust-trapping portion.
In this conventional engine cutter wherein an air-cooled internal combustion engine is employed as a driving source for rotating the disk cutter, a fan for generating an air flow for sucking and discharging the dust that has been trapped in the dust-trapping portion is disposed in addition to a cooling fan for the engine. Thus, according to this conventional engine cutter, a couple of fans are required to be equiped, i.e. one for cooling the engine, and the other for sucking and discharging dust.
Therefore, this conventional engine cutter is defective in that the structure thereof is rather complicated, and that the manufacturing cost thereof is inevitably increased.
The present invention has been made to cope with the aforementioned problems, and therefore an object of the present invention is to provide an engine cutter wherein a single fan is employed for both cooling the engine and sucking and discharging dust, thereby simplifying the structure of engine cutter and at the same time, saving the manufacturing cost thereof.
With a view to realize the aforementioned object, the present invention provides an engine cutter which essentially comprises a disk cutter, an air-cooled internal combustion engine for rotating the disk cutter, a safety cover partially encasing the disk cutter, a dust-trapping portion which is mounted on the safety cover for trapping and discharging dust to be generated from a cutting work by the disk cutter, and a fan to be driven by the engine not only for generating an air flow for sucking and discharging the dust that has been trapped in the dust-trapping portion but also for generating a cooling air flow for cooling the internal combustion engine.
In a preferable embodiment of the engine cutter according to the present invention, part of the air flow generated by the fan is branched so as to be utilized as a cooling air flow for cooling the internal combustion engine, and the rotation of the internal combustion engine is transmitted to the fan through an acceleration of the rotation of the internal combustion engine, or alternatively, the output shaft of the internal combustion engine is directly coupled to the fan.
In another preferable embodiment of the engine cutter according to the present invention, the dust-trapping portion is preferably constituted by a trap-guiding plate interposed between the opposite surfaces of the cutter and the safety cover, and a dust sucking port disposed at a midway of a passageway for flowing the air flow generated by the fan.
In an additional preferable embodiment of the engine cutter according to the present invention, a dust-collecting bag having air permeability is attached to a downstream end of a passageway for flowing the air flow generated by the fan.
According to the engine cutter of the present invention which is constructed as explained above, since a single fan is employed not only for sucking and discharging the dust, but also for cooling the internal combustion engine, the construction of the cutter can be simplified, the total weight of the cutter can be reduced, and the manufacturing cost of the cutter can be saved.
Additionally, when the cutter is constructed such that the rotation of the internal combustion engine is transmitted to the fan through an acceleration of the rotation of the internal combustion engine, the quantity of air demanded for cooling the engine as well as the quantity of air demanded for sucking and discharging dust can be sufficiently secured without so greatly increasing the diameter of the fan.
This specification includes part or all of the contents as disclosed in the specification and/or drawings of Japanese Patent Application No.353475/1999, which is a priority document of the present application.